THE ALIMENTARY CANAL. 85 
one from the windpipe, 
guarded by the epiglot- 
tis; one from the mouth, 
with a fleshy curtain call- 
ed the soft palate ; and 
one from the cesophagus. 
It is the natural passage 
for food between the 
mouth and the cesopha- 
gus, and of air between 
the nostrils and wind- 
pipe. Like the mouth, 
it is lined with a soft 
mucous membrane. 
The esophagus is a 
long and narrow tube, 
formed of two muscu- 
lar layers: in the out- 
side one, the fibres run 
lengthwise; in the oth- 
er, they are circular. 
It is also covered more 
or less with a sheath of 
striated fibres, and lined 
with mucous membrane. 
While in all Fishes, Rep- 
tiles, and Birds the ven- 
tral chamber is one, in 
Mammals it is divided, 
by a_ partition called 
the diaphragm, into two 
Fia. 49.—Digestive Apparatus of Man: 1, tongue; 2, pharynx; 3, esophagus; 4, soft 
palate; 5, larynx; 6, palate; 7, epiglottis; 8, thyroid cartilage; 9, beginning of 
spinal marrow; 10,11, 12, vertebrze, with spinous processes; 13, cardiac orifice of 
stomach; 14, left end of stomach; 18, pyloric valve; 19, 20, 21, duodenum; 22, 
gall-bladder; 27, duct from pancreas; 28, 29, jejunum of intestine; 30, ileum; 
34, cecum; 36, 37, 38, colon, or large intestine; 40, rectum. 
